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<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    
    <script>
        // 只有0、NaN、null、undefined、空字符串是false，其他都是true
        if ('false') {
            alert('我进到if里了')
        }else {
            alert('我进到else')
        }
    </script>
</body>
</html>